CVE-2020-25506Known exploitationPublic exploitNetwork attack vector

Unauthenticated command execution via unsanitized NTP parameter

Published Feb 2, 2021 · Updated Oct 21, 2025

OS command injection in D-Link DNS-320 firmware 2.06B01 Revision Ax allows remote attackers to execute arbitrary commands. The system_mgr.cgi component passes the f_ntp_server HTTP parameter into command processing without neutralizing shell syntax. An unauthenticated network request can therefore run commands on the NAS and install malware or alter data and services.

CVSS severity9.8
Critical
EPSS probability99.97%
Next 30 days · Nov 1, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

OS command injection in D-Link DNS-320 firmware 2.06B01 Revision Ax allows remote attackers to execute arbitrary commands. The system_mgr.cgi component passes the f_ntp_server HTTP parameter into command processing without neutralizing shell syntax. An unauthenticated network request can therefore run commands on the NAS and install malware or alter data and services.

The record

CVE
CVE-2020-25506
Published
Feb 2, 2021
Updated
Oct 21, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-78, T1190, T1059.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 2, 2021CVE publishedPublication date reported by the CVE source.
  2. Feb 16, 2021Exploitation reportedMirai campaign exploiting D-Link DNS-320
  3. Oct 21, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsShadowserver observations through Sep 28, 2026. Gaps indicate unavailable data.
Sep 22, 2026Sep 28, 2026
View daily counts
Reporting dayUnique IPs
Sep 22, 20269
Sep 23, 20262
Sep 24, 20267
Sep 25, 202612
Sep 26, 20263
Sep 27, 202616
Sep 28, 20268
Latest reporting daySep 28, 2026
Latest daily unique IPs8
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationReported
Public exploitPublished

Weakness, pattern, technique

CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
T1190Exploit Public-Facing Application
T1059.004Unix Shell

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Reported exploitation

Technologies

Your stack

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Your stack

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